They're essentially the same, with networking options being the big difference.
Do you want to stream music from Pandora, Reciva, Shoutcast or from your home network? If so, the RD-705i is the receiver for you. If not, you'll be more than happy with the RD-7505.
Sherwood's new amps are practically identical, with the addition of networking capabilities being the biggest difference between the two. Both are 3D ready and both boast HDMI 1.4 inputs with repeater circuitry. Both use discrete power amplifiers capable of 100 watts at 8 ohms and both utilize 192kHz/24 bit DACs.
The pair of Sherwood's AV receivers also include the SNAP system – an automated system that, with the help of a microphone that comes bundled with the receiver, configures the receiver to sound as good as possible in your room.
You'll be able to pick up both receivers in November, with the RD-7505 coming in at $399 and the RD-705i launching at $499.